[PATCH v2] rtla: Stop the record trace on interrupt

[PATCH v2] rtla: Stop the record trace on interrupt

[Crystal Wood]

Before, when rtla got a signal, it stopped the main trace but not the
record trace.  With "--on-end trace", this can lead to
save_trace_to_file() failing to keep up, especially on a debug kernel. 
Plus, it adds post-stoppage noise to the trace file.

Signed-off-by: Crystal Wood <crwood@redhat.com>
---
v2: clarify that this matters for --on-end trace

 tools/tracing/rtla/src/common.c   | 19 +++++++++++--------
 tools/tracing/rtla/src/common.h   |  1 -
 tools/tracing/rtla/src/timerlat.c |  2 +-
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/tools/tracing/rtla/src/common.c b/tools/tracing/rtla/src/common.c
index 35e3d3aa922e..effad523e8cf 100644
--- a/tools/tracing/rtla/src/common.c
+++ b/tools/tracing/rtla/src/common.c
@@ -10,7 +10,7 @@
 
 #include "common.h"
 
-struct trace_instance *trace_inst;
+struct osnoise_tool *trace_tool;
 volatile int stop_tracing;
 int nr_cpus;
 
@@ -21,12 +21,16 @@ static void stop_trace(int sig)
 		 * Stop requested twice in a row; abort event processing and
 		 * exit immediately
 		 */
-		tracefs_iterate_stop(trace_inst->inst);
+		if (trace_tool)
+			tracefs_iterate_stop(trace_tool->trace.inst);
 		return;
 	}
 	stop_tracing = 1;
-	if (trace_inst)
-		trace_instance_stop(trace_inst);
+	if (trace_tool) {
+		trace_instance_stop(&trace_tool->trace);
+		if (trace_tool->record)
+			trace_instance_stop(&trace_tool->record->trace);
+	}
 }
 
 /*
@@ -273,11 +277,10 @@ int run_tool(struct tool_ops *ops, int argc, char *argv[])
 	tool->params = params;
 
 	/*
-	 * Save trace instance into global variable so that SIGINT can stop
-	 * the timerlat tracer.
+	 * Expose the tool to signal handlers so they can stop the trace.
 	 * Otherwise, rtla could loop indefinitely when overloaded.
 	 */
-	trace_inst = &tool->trace;
+	trace_tool = tool;
 
 	retval = ops->apply_config(tool);
 	if (retval) {
@@ -285,7 +288,7 @@ int run_tool(struct tool_ops *ops, int argc, char *argv[])
 		goto out_free;
 	}
 
-	retval = enable_tracer_by_name(trace_inst->inst, ops->tracer);
+	retval = enable_tracer_by_name(tool->trace.inst, ops->tracer);
 	if (retval) {
 		err_msg("Failed to enable %s tracer\n", ops->tracer);
 		goto out_free;
diff --git a/tools/tracing/rtla/src/common.h b/tools/tracing/rtla/src/common.h
index 51665db4ffce..eba40b6d9504 100644
--- a/tools/tracing/rtla/src/common.h
+++ b/tools/tracing/rtla/src/common.h
@@ -54,7 +54,6 @@ struct osnoise_context {
 	int			opt_workload;
 };
 
-extern struct trace_instance *trace_inst;
 extern volatile int stop_tracing;
 
 struct hist_params {
diff --git a/tools/tracing/rtla/src/timerlat.c b/tools/tracing/rtla/src/timerlat.c
index f8c057518d22..637f68d684f5 100644
--- a/tools/tracing/rtla/src/timerlat.c
+++ b/tools/tracing/rtla/src/timerlat.c
@@ -202,7 +202,7 @@ void timerlat_analyze(struct osnoise_tool *tool, bool stopped)
 		 * If the trace did not stop with --aa-only, at least print
 		 * the max known latency.
 		 */
-		max_lat = tracefs_instance_file_read(trace_inst->inst, "tracing_max_latency", NULL);
+		max_lat = tracefs_instance_file_read(tool->trace.inst, "tracing_max_latency", NULL);
 		if (max_lat) {
 			printf("  Max latency was %s\n", max_lat);
 			free(max_lat);
-- 
2.54.0